A known type of tuning device of a stringed instrument is seen in U.S. Pat. No. 4,213,370 (Jones) where a peg and worm gear is affixed in a cavity formed by facing panels of a guitar body. The peg has a transverse and axial bore into which a string end is passed and a connecting portion of a string key connected to the peg through the worm gearing. U.S. Pat. No. 4,625,613 (Steinberger) shows a tuning unit including jaws which grasp a ball-headed string and is movable by an attached knob which tightens or loosens the string. U.S. Pat. No. 4,625,614 (Spercel) discloses another worm gear and key device with a string rotatable around the peg. It also shows a clamping pin for initially clamping a string end. U.S. Pat. Nos. 4,643,069 and 4,648,303 show other variants of a worm gear for winding a string around a rotatable peg.
The above tuning devices generally involve the imposition of frictional forces by use of lock washers or fastening screws so that the tuning knob resists needed rotational movement and becomes difficult to turn by hand, particularly making fine tuning adjustments for short increments of rotation difficult to precisely pitch tune the strings by hand. Oft times these devices require the need for an adjusting tool. Pinion and worm gear combinations do not normally result in more than about a 12 to 1 tuning ratio whereas it is preferable to have fine tuning ratios of the order of 40 to 1. The presence of worm gears and pinions also result in slippage or play commonly associated with worn worm tuning gear mechanisms.